Resistance band training or general exercise in multidisciplinary rehabilitation of low back pain? A randomized trial.

Multidisciplinary biopsychosocial rehabilitation has been recommended for chronic low back pain (LBP), including physical exercise. However, which exercise modality that is most advantageous in multidisciplinary biopsychosocial rehabilitation is unclear. In this study, we investigated whether multidisciplinary biopsychosocial rehabilitation could be more effective in reducing pain-related disability when general physical exercise was replaced by strength training in the form of progressive resistance training using elastic resistance bands. In this single-blinded (researchers), randomized controlled trial, 99 consenting adults with moderate-to-severe non-specific LBP were randomized to three weeks of multidisciplinary biopsychosocial rehabilitation with either general physical exercise or progressive resistance band training and were then instructed to continue with their respective home-based programs for nine additional weeks, in which three booster sessions were offered. The primary outcome was between-group difference in change on the Oswestry Disability Index (ODI) at 12 weeks. Due to early dropouts, data from 74 participants (mean age: 45 years, 57% women, mean ODI: 30.4) were obtained at baseline, 61 participants were followed-up at 3 weeks, and 46 at 12 weeks. There was no difference in the change in ODI score between groups at 12 weeks (mean difference 1.9, 95% CI: -3.6, 7.4, P = .49). Likewise, the change in secondary outcomes did not differ between groups, except for the patient-specific functional scale (0-10), which favored general physical exercise (mean difference 1.4, 95% CI: 0.1, 2.7, P = .033). In conclusion, this study does not support that progressive resistance band training compared to general physical exercise improve outcomes in multidisciplinary biopsychosocial rehabilitation for patients with non-specific LBP.

The Effect of Performing Bi- and Unilateral Row Exercises on Core Muscle Activation.

The purpose of the study was to compare core muscle activation in 3 different row exercises (free-weight bent-over row, seated cable row and machine row) performed unilaterally and bilaterally, at matched effort levels. 15 resistance-trained men (26.0±4.4 years, 81.0±9.5 kg, 1.81±0.07 m) performed the exercises in randomized order. For erector spinae and multifidus, EMG activities in unilateral machine- and cable row were 60-63% and 74-78% of the bilateral performance (P≤0.036). For external oblique, the EMG activities recorded during bilateral exercises were 37-41% of the unilateral performance (P≤0.010). In unilateral cable- and machine rows, the EMG activities in external oblique and multifidus were 50-57% and 70-73% of the free-weight row (P≤0.002). In bilateral free-weight row, EMG activity in erector spinae was greater than bilateral machine- (+34%, P=0.004) and unilateral free-weight rows (+12%, P=0.016). For rectus abdominis there were no significant differences between conditions. In conclusion, 1) free-weight row provided greater EMG activity in erector spinae (bilaterally and unilaterally) and multifidus (unilaterally) than machine row; 2) unilateral performance of exercises activated the external oblique more than bilateral performance, regardless of exercise; and 3) generally bilateral performance of exercises provided higher erector spinae and multifidus EMG activity compared to unilateral performance.

Leisure-time physical activity and disability pension: 9 years follow-up of the HUNT Study, Norway.

The objective of this study was to prospectively examine the association between leisure-time physical activity and risk of disability pension, as well as risk of disability pension because of musculoskeletal or mental disorders in a large population-based cohort. Data on participants aged 20-65 years in the Norwegian Nord-Trøndelag Health Study 1995-1997 (HUNT2) were linked to the National Insurance Database. Cox regression was used to calculate hazard ratios (HR) and 95% confidence intervals for disability pension across physical activity categories. During a follow-up of 9.3 years and 235,657 person-years, 1266 of 13,823 men (9%) and 1734 of 14,531 women (12%) received disability pension. Compared with individuals in the inactive group, those in the highly active group had a 50% lower risk of receiving disability pension (HR for men: 0.50, 0.40-0.64; women: 0.50, 0.39-0.63). After comprehensive adjustment for potential confounders, the risk remained 32-35% lower (HR for men: 0.68, 0.53-0.86; women: 0.65, 0.51-0.83). The associations were stronger for disability pension due to musculoskeletal disorders than mental disorders. In summary, we observed strong inverse associations between leisure-time physical activity and disability pension. Our findings strengthen the hypothesis that leisure-time physical activity may be important for occupational health in reducing disability pension.

Muscle activation and strength in squat and Bulgarian squat on stable and unstable surface.

The aim of the study was to compare muscle activity using the same relative resistance in squats and Bulgarian squats on stable and unstable surface. Muscle strength and activity were assessed by 6-repetition maximum and concomitant surface electromyography. A cohort of 15 resistance-trained males performed the exercises on the floor or a foam cushion in randomized order. The muscle activity was greater in biceps femoris (63-77%, p<0.01) and core muscle external obliques (58-62%, p<0.05) for the Bulgarian squat compared to regular squats, but lower for rectus femoris (16-21%, p<0.05). Only Bulgarian squat showed differences concerning the surface, e. g. the unstable surface reduced the activation of erector spinae (10%, p<0.05) and biceps femoris (10%, p<0.05) compared to a stable surface. There were similar activations in the vasti muscles and rectus abdominis between the different exercises (p=0.313-0.995). Unstable surfaces resulted in a load decrement of 7% and 10% compared to stable surfaces (p<0.001). In conclusion, the squat was somewhat favorable for the activation of agonists, whereas Bulgarian squat was advantageous for the antagonist and somewhat for core muscles. Bulgarian- and regular squats complement each other, and it may be useful to include both in a periodized resistance training program.

Structural brain changes after 4 wk of unilateral strength training of the lower limb.

Strength training enhances muscular strength and neural drive, but the underlying neuronal mechanisms remain unclear. This study used magnetic resonance imaging (MRI) to identify possible changes in corticospinal tract (CST) microstructure, cortical activation, and subcortical structure volumes following unilateral strength training of the plantar flexors. Mechanisms underlying cross-education of strength in the untrained leg were also investigated. Young, healthy adult volunteers were assigned to training (n = 12) or control (n = 9) groups. The 4 wk of training consisted of 16 sessions of 36 unilateral isometric plantar flexions. Maximum voluntary isometric contraction torque was tested pre- and posttraining. MRI investigation included a T1-weighted scan, diffusion tensor imaging and functional MRI. Probabilistic fiber tracking of the CST was performed on the diffusion tensor imaging images using a two-regions-of-interest approach. Fractional anisotropy and mean diffusivity were calculated for the left and right CST in each individual before and after training. Standard functional MRI analyses and volumetric analyses of subcortical structures were also performed. Maximum voluntary isometric contraction significantly increased in both the trained and untrained legs of the training group, but not the control group. A significant decrease in mean diffusivity was found in the left CST following strength training of the right leg. No significant changes were detected in the right CST. No significant changes in cortical activation were observed following training. A significant reduction in left putamen volume was found after training. This study provides the first evidence for strength training-related changes in white matter and putamen in the healthy adult brain.